Machine for testing blasting cap shells



April 7, 1942.

J. STUART, 2D

MACHINE FOR TESTING BLAISTING CAP SHELLS Filed Ded. 22, 1959 JOSEPHSTUART 11 INVENTOR.

a. Lu

ATTORNEY.

Patented Apr. 7, 1942 UNITED STATES PATENT OFFICE.-

Joseph Stuart, II, :331, Del., assignor Hercules Powder Company,Wilmington, Del.,

a corporation oi Delaware Application December 22, 1939, Serial No.310,578

' 3 Claims. .(CL 73-41) This invention relates totesting machines, andcome the foregoing difliculties and disadvan more particularly to amachine for testing blasttages."

ing cap shells and the like.

Blasting cap shells usually are between about .22 and .30 of an inch indiameter and between about 1 /2 and 6 /2 inches in length, and areconstructed of a ductile metal, such as, copper, aluminum, or bronze,brass or other suitablealloys. These shells are formed by a successionof drawing operations which elongate the shell while 10 maintaining adesired diameter. In the course of these operations, the metal issubjected to severe strains which may cause the metal to rupture at oneor more points and form holes in the shell. Such holes are formed moreparticul5 larly during the latter stages of the final drawing operation,when due to the elongation of the shell, the metal has become extremelythin.

If such holes are not detected, the weakened walls of such imperfectshells may buckle while pressing a charge of explosive therein which maycause an explosion damaging the press. This will necessitateinterrupting the operation of the press until resulting debris iscleared and the presshas been repaired. It the shells having holestherein are filled, portionsof the charge may be forced through theholes and be exposed. Friction caused by the rubbing oi adiacent shellsmay set off the charge while the blasting caps are being shipped orstored.

A further and serious dimculty is that moisture may enter through theholes and render the charge in the cap insensitive. if the charge in acap fails to explode, the cap and explosive in. a bore holc may berecovered by washing or blowing them out with air or water, or anothercharge of explosive may be positioned and exploded. in a bore holeadjacent the charge which has not been exploded by reason or failure oithe cap. These operations are hazardous and Also, an

frequently result in personal injury. explosive charge which has notbeen exploded due to the failure of the cap, may be scattered in thebroken material produced by the explosion of adjacent charges. Thus whenthe muck is removed, the scattered explosive may be accidentallydetonated, and cause injury. Another difllculty resulting from thefailure of one or more caps-to set ofl portions of the explosive is thatthe muck is not properly disintegrated or is of the wrong size. Also,objectional humps or toes may remain which are difllcult and costly toremove.

An object of the present invention is to over- Another object is toprovide a simple, inexpensive machine for testing blasting cap shellswhich is readily constructed of a minimum number oi parts.

Another object is to provide a machine for testing shells which is'rapid in operation and with which the amountol labor required to insDectshells is reduced to a minimum.

Another object is to provide a machine for testing shells which ishighly accurate, reduces the labor cost of testing shells to a minimum,and is not subject to human error.

Another object is to provide a machineior testing shells which may beoperated automat i cally or semi-automatically if desired.

Another object is to provide a machine which tests the shells. andautomatically separates the imperfect and perfect shells.

Another object is to provide a shell testing machine which is readilyadjusted to accommodate shells of diflerent lengths and diameters.

Other and further objects will be obvious upon an understanding of theillustrative embodiment about to be described, or will be indicated inthe appended claims. and various advantages not referred to herein willoccur to one skilled in the art upon employment of the invention inpractice.

In the accompanying drawing, Fig. 1 is an elevational view, partly insection, illustrating an embodiment of the invention;

Fig. 2 is a sectional view, taken along line 2-2 on Fig. l;

which first apply a vacuum to the shells to hold them on the rotatablemember and thereafter vent or supply air pressure for discharging theshells from the rotatable member. Suitable automatic feeding means maybe utilized to feed the shells to'the testing stations or the shells maybe placed thereon manually. These stations are adapted to support theshells on the rotatable member. A vacuum is then applied to hold theshells on the member and thevacuum is then shut off, but the vacuumcreated in a shell is adapted to be maintained if the shell does nothave any holes therein. The rotatable memher then is rotated to move theshells into a position whereby they project downwardly from thesupporting stations, and if the shells have holes therein, they willfall by gravity from the member. The perfect shells are retained on thesupporting stations which then are moved to another position where theyare vented to release the vacuum or air pressure is applied to dischargethe shells.

Referring again to the drawing, and more particularly to Figs. 1 to 5,there is shown an upright member or supporting bracket in for mounting ashell testing device H which comprises a stationary valve member l2 anda rotatable member l4 (Fig. 2) adapted to rotate in a vertical planeabout a horizontal axis. The valve member l2 may have a collar portionl5 extending rearwardly through an aperture IS in the bracket l and thecollar portion I has an aperture H which serves as a. bearing for arotatable shaft H9. The valve member l2 also has a circular flange 20which may be secured to the bracket by bolts 2| or the like (Figs. 2 and3).

The front side of the flange provides an annular or circular valve face22 (Fig. 4) which has a groove or recess 24 spaced inwardly from theperiphery of the flange. The recess 24 preferably is arcuate and extendscircumferentially upon the face for about 90. This recess is connectedto a. source of vacuum, for example, by a circumferential groove orrecess 25 having a port or aperture 26 therein which is connected to avacuum supply line 21 (Fig. 3) extending through apertures 29 and 30' inthe flange and bracket, respectively. The valve face further is providedwith an aperture or port 3| spaced circumferentially from the vacuumrecess 24 a little less than about 90 in a counter-clockwise direction.This port has connected thereto a tube 32 in communication with theatmosphere or a supplyof air pressure and the tube 32 extends throughapertures 34 and 35 in the flange and base, respectively. 7

The shaft l9 extending through the collar iii of the valve member has aforward end portion of reduced diameter to provide a shoulder 4| invertical alignment with the valve face 22. This shoulder serves as anabutment for the rotatable member l4, about to be described, which ismounted on the reduced portion 40 of the shaft 5 and issecured thereonby a nut member 42 threaded to the end of the shaft. The nut member isadapted to hold the rotatable member against the shoulder 4|, but may beeasily unscrewed to permit removal of the rotatable member forinspection and repair.

The rotatable member M, which will now be described in detail,preferably is disc-shaped and has a cylindrical peripheral surface 45.On this surface a suitable number of shell supporting stations, forexample four, may be provided. As illustrated more particularly in Fig.2, each station may comprise a substantially radially outwardlyprojecting finger or pin 48 over which a shell B may be telescoped, andthe finger may be tapered outwardly to facilitate receiving the shells..If desired, each finger may have a longitudinal slot or groove 48 atoneside to facilirelief port 3| (Fig. 2).

tate vacuumizing the shell adjacent its open end. The inward end of thefinger has a threaded portion 41 of reduced diameter which is threadedinto a threaded aperture 48 of the rotatable member. The fingers in thismanner may be readily removed and-replaced by fingers of another sizesuitable for supporting shells of a different length and diameter.

The supporting stations are further provided with a resilient portionsuch as a rubber washer 50, seated in a recess 5| on the peripheralsurface of the rotatable member and held in place bya shoulder 52 on thepin to provide an airtight seal at the joint between the threadedaperture 49 and the threaded portion 41. These washers are adapted to beengaged by the open end of a shell and when vacuum is applied,.seal theshell at the point of engagement.

In order to connect the fingers to the source of vacuum whereby theywill serve to evacuate the shells and hold them on the supportingstations, each finger hasa longitudinal bore or aperture 55 incommunication with a radially extending conduit portion 56 in therotatable member. The conduit portion 56 meets a second conduit portion5'! extending transversely to the rear face 59 of the rotatable member.The rear face 59 is positioned for rotation against the valve face 22 tocomplete the valve construction. The conduit portions 51 in the rearface are adapted to register with the vacuum recess 24 to supply vacuumto the fingers or pins and are adapted to be closed by the valve facesurface 60 to disconnect the supply of vacuum, and

also are adapted to register with the vacuum The shells may bepositioned on the fingers in any suitable manner, for example, manuallyor may be fed by an automatic device.

mittently by a suitable Geneva drive which is well known and need not beshown. The feeding device may comprise a pin having a bore 66 forreceiving the closed end of a shell and suitable means (not shown) forreciprocating the pin to pick up a. shell from a stack of shells in a.

' magazine (not shown) and telescope the shell over a pin. The feed pinslides through the bore 70 of a guide block H (Figs. 1 and 5) secured tothe bracket Ill, and this block is positioned adiacent the path of theouter ends of the fingers and in alignment with one position at whichthe fingers are at rest. The feed pin preferably is moved by aneccentric mechanism (not shown) which feeds a shell and moves away fromthe fingers while the fingers are at rest and picks up another shellwhile the fingers are moved from one position to another.

In Fig. 6, a modified shell supporting station is shown, which comprisesa sleeve 15 having a threaded nipple 41' threaded into the aperture theshells are fed is essentially the same and the.

description of this method will serve for both manual and automaticfeeding.

Preferably, a shell is placed on a finger at the left side of the devicewhile it is in horizontal position or has been movedslightly into Toaccomplish this, the shaft I9 is rotated clockwise inter-' upwardlyinclined position, as indicated at A in Fig. 1. When in this positionthe conduit 51 of the pin is at A, indicated in dotted lines in Fig. 4,and is in communication with the vacuum recess 24, whereby the vacuum iseffective to withdraw air in the shell and cause the open end of theshell to engage the resilient member 50.

As the shell is moved by rotation of the rotatable member l4 towards theposition, indicated as B in Fig. 1, the conduit 51 remains incommunication with the vacuum recess 24, so that the shell if free fromholes is substantially vacuumized and is sucked against the resilientmember 50. Just prior to reaching position B, the valve face surface 50(Fig. 4) closes the conduit 51, indicated at position B, and shuts offthe vacuum.

If the shell has a hole in it, air will enter into the hole and destroywhatever partial vacuum might have been created in the shell. Thus, theshell will be resting loosely on the finger and will not be suckedagainst 'the resilient member 50. As the finger moves into position C(Fig. 1) it will dip downwardly and the shell, if not held by suction,due to being imperfect, will slide by gravity from the finger. v atposition C by reason of being imperfect fall into a receptacle and arekept out of the production line. I

The shells which are free from holes, when once vacuumized will maintaina suflicint vacuum to hold the open ends of the shells against theresilient members 50 so long as'the conduit 51 is kept closed by thevalve surface 60 to prevent the escape of the vacuum. Thus, a-perfectcap while moving from positions B to C to D is held on the rotatablemember l4 even when the finger dips downwardly. At position D'(Fig. 3)

the conduit 51 registers with the port.3l connected to the atmosphere,whereby the vacuum is destroyed and the shell falls by gravity atposition D (Fig. 1) into a receptacle for the perfect shells. If desiredthe port 3| may be connected to a'supply of air pressure whichpositively discharges the shell from the finger. This is desirable inthe event the open end of the shell has adhered to the resilient member50 or 50'.

From the foregoing description it will be seen that the presentinvention provides a shell testing machine which will separate shellshaving holes therein from those free from holes. The machine is rapid inoperation and automatically separates the good and bad shells.Furthermore, the machine can be economically constructed and can beoperated ata minimum labor cost. The machine is rugged in constructionand can readilywithstand any rough usage to which it may be subjected.

As various changes may be made in the form, construction and arrangementof the parts here- The shells discharged in, without departing from thespirit and scope of the invention, and without sacrificing any of itsadvantages, it is to be understood that all matter herein is to beinterpreted as illustrative and not in a limiting sense.

What Iclaim and desire to protect by Letters Patent is:

1. In a machine for vacuum and classifying closed-end tubular shells ofrelatively greater length than diameter such as blasting caps; thecombination of a vertical, cylindrical, rotatable member, mounted upon ahorizontal axis, a plurality of elongated fingers each having a boreextending therethrough and extending radially from the periphery of thesaidmember, said fingers being at least longer than half the length ofsaid shells and being capable of receiving and mechanically supportingsaid shells adapted to be inspected and classified, a feeding fmeansdisposed radially of and at'theside of by shells are supported by thesaid fingers during.

application of vacuum. 7

2. In a machine for vacuum inspecting and classifying closed-end tubularshells of relatively greater length than diameter such as blasting caps;the combination of a feeding mechanism comprising a tubular guide havinga reciprocating plunger acting therein, a vertical, cylindrical.rotatable member mounted upon a. horizontal axis, elongated fingers eachhaving a bore therethrough and extending radially from the periphery ofsaid rotatable member, said feeding mechanism being located radially ofand at the side of said rotatable member and adapted for'movingsaidshells onto said fingers, said fingers being at least longer than halfthe length of said shells and being capable'of receiving andmechanically supporting said shells, a three-way valve mechanismoperatively connected with said member in successive fluid communicationwith the bore portion of each elongated finger and valving each fingerto a source of vacuum during said fingers periphery rotation from onelateral extremity to the top of the circumferential travel and closingeach finger to said source of vacuum during its rotation from the top tothe bottom of its travel and venting each finger to a source of airduring its rotation from the bottom of its travel to the said lateralextremity, whereby shells are supported by the said fingers duringapplication of vacuum.

3. In a blasting cap shell testing machine, the combination of avertically disposed, cylindrical,

rotatable shell supporting means mounted upon a horizontal axis, aplurality of elongated fingers each having an opening therethroughterminating in a common face of said shell supporting means, saidfingers being atleast longer than chamber and a vacuum releasing chamberdis-' posed in the upper and lower left-hand' quadrant respectively ofsaid valve means, and means adapted to close saidfinger openings aftermove ment of said openings away from said vacuum producing chamber andprior to movement into said vacuum releasing chamber.

JOSEPH s'roaa'r, n

